scorp508

Thank you in advance for any help you may be able to offer.

Car: 1987 Corvette Coupe
Alternator: 105 amp

Ok I have almost exhausted my ideas for why <b>Fusible Link C</b> keeps blowing on my charging sytem. This is the fusible link in-line between the 10 gauge wire on the alternator to the jumpstart junction block behind the battery which itself is a (+) connection right off the battery.

The very last thing I found tonight before coming inside is that I am getting continuity between ground and the jumpstart junction block. I am pretty sure this isn't right at all. :nonod:

Things so far gone wrong and/or found.

1. Finished installing engine and systems.
2. Charging system was fine.
3. Went for test drive and 3 miles out the entire electical system shutdown for about 1/2 second and came back. From this point on the charging system was failed.
3a. Assumed dead alternator as always, installed brand new non-reman unit immediately. Still no charge.
4. Inspection showed Fusible Link C blown.
5. Continuity on cables was fine, no shorts found.
6. Installed new 30 Amp fusible link. Continuity checks out.
7. Start car, fusible link blows immediately.
8. Jump junction block and alternator momentarily to test, charging system works.
9. Search for things wrong.
10. Starter connections extremely loose.
11. Tighten starter connections firmly, suspect loose connections creating extreme high current draw.
12. Install 30 amp circuit breaker (i'm not going to keep doing those damn links!)
13. Start car, still no dice. Charges.... stops.... charges.... stops..... so the breaker is opening and closing.
14. Inspect for more.
15. Find continuity between ground and jumpstart junction block stud where all terminals are connected. Damnit.

I'm out of ideas. It looks like I'm going to have to search for pinched wires aren't I? There is a ground strap above the oil filter that I am not sure is routed right. Does this one go to the frame?

Below is the wiring diagram (its huge sorry, wanted to make SURE you could read it). Perhaps I do not have the correct fusible link? I am using a 30 amp. The alternator lead is 10 gauge wire, the other side of the original fisible link was the what appeared to be 12 gauge.

Snowdog 91 Formula

Did you try another alternator?

scorp508

Yes, sorry let me edit that in there. That was the first assumption before seeing the blown link so I installed a brand new non-reman unit.

91L98Z28

When the system is charging, what is the voltage at the jumpstart junction block?

If you leave the battery plugged in overnight, is it dead the next morning?

Is fusible link B ok?

vettes always have weird ground systems because of the fiberglass body...check all your grounds make sure they are good...

otherwise, don't know

meridius

Heres a thought for you, if the starter is shorted out inside it may be causing a short to ground, but its sounding to me like you have a wiring problem somewhere.

Andy Bush

I bet you definately have a shorted wire between the fuse and the alternator.

And I also rekon it is due to a wire that has the insulation melted because it is too near the exhaust.
You say it was ok for a few minutes which is all it would take to melt the insulaiton. You just put the engine back and that is the most likely event that relocated the wire. The wire does run on some models from the back of the engine, and could easily fall onto the exhaust

But the wire will move around and only short occaisionally.

If the jump start block has no resistance the earth, there is a short. If sometimes it is not there, until you start, that indicates the wire is moving and touching.

You say the power went down for a moment and came up after which the fuse was blown. The power would stay down until the fuse blew, because it was shorting to earth through the fuse and the fault.

Please let me know if this guess is correct

Andy Bush

PS
If you can't find the short, try running a new wire directly from fuse C to the alternator.